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Air in Fuel Lines.

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AlanMcR
Posts: 7729

Re: Air in Fuel Lines.

Post#151 » Wed Mar 18, 2020 1:29 pm

To test the injectors you need a pop tester. This will allow you to verify spray pattern and opening pressure. Also you need a set of the heat shield disks that seal the opening when the injectors are re-installed.
...Alan

Court
Posts: 812

Re: Air in Fuel Lines.

Post#152 » Wed Mar 18, 2020 2:53 pm

Thank you Alan,

Beyond my capability and capacity for Sure!

For everyone’s amusement I asked MB for a price on these return lines.... there must be some mistake I told them since they want $42 for each six inch segment. Haha haha...........

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AlanMcR
Posts: 7729

Re: Air in Fuel Lines.

Post#153 » Wed Mar 18, 2020 3:33 pm

And people wonder why I work on my on vehicles.
...Alan

Court
Posts: 812

Re: Air in Fuel Lines.

Post#154 » Wed Mar 18, 2020 3:47 pm

Yes agreed... (greed) ... so my research so far indicates that polyurethane 1/8th" tubing looks like my best option for availability and cost.... like about $4 total. At that price can but spare tubing ,,, and also can observe flow possibly in the tubing ,,, but it is only rated to 70 degrees celsius ,,,158 F... so maybe i need to order Viton from the USA,,,

Court
Posts: 812

Re: Air in Fuel Lines.

Post#155 » Wed Mar 18, 2020 4:02 pm

Well ok ,,, so I discovered it is not Department of Transport approved ,,,so if there was any issue with an engine fire ,,,no insurance coverage,,,, I think I will order a VW kit online and modify if needed... injector barbs must be all the same I would think.

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AlanMcR
Posts: 7729

Re: Air in Fuel Lines.

Post#156 » Wed Mar 18, 2020 4:11 pm

Needs to be much higher than 70C. The Viton is rated to 200C.
...Alan

Court
Posts: 812

Re: Air in Fuel Lines.

Post#157 » Wed Mar 18, 2020 4:26 pm

No viton in Vancouver...going to order from USA or ,,, might just get line from Mercedessource,,, only 16.95 plus shipping ,,, he is not far from here so should be reasonable,,,, waiting for $$ from a local guy recommended by Minh.

Court
Posts: 812

Re: Air in Fuel Lines.

Post#158 » Thu Mar 26, 2020 9:01 am

So today I expect to receive replacement return line ...Viton with a cool green coloured braid wrapping. It is the MB spec size.

Once I replace these I will see if this helps to resolve the air bubbles issue.

I am considering how to best do a diesel purge without allowing significant air into the system.

It seems to me since the pump sucks fuel from the tank I should be able connect the diesel purge fluid supply to the prefilter ( disconnecting the permanent one from the heater). But I think I should somehow stop fuel from flowing back into tank by squeezing off one of the flexible line connectors to the hard lines. I assume this would keep that line full. Although I think really that the air problem would arise within the pumping / sucking circuit as Alan has suggested possible from cavitation of the the fuel due to the power of the pump.

The return line can be relocated to the diesel purge source.

But before I do the purge I am thinking I should try to resolve if there is a leak or not in the pump circuit. To that end I thought I should go all out and remove the IM for easy access to lines etc.

So ... I have researched this and am assembling my tools. My concern is how to get at the bolts under the IM. But found some stuff at the Peachparts site. Also need to source new gaskets.

So as these things go I am thinking ..... if I have it off should I replace the glow plugs ? It has 99,900km on the engine. I have heard of problems with them getting stuck on removal ... so would approach this with trepidation.

Interesting how one can quickly escalate a sleuthing project into a minor overhaul.

Anyway would appreciate thoughts in the glowplug replacement and advice on the IM removal / replacement.

User avatar
AlanMcR
Posts: 7729

Re: Air in Fuel Lines.

Post#159 » Thu Mar 26, 2020 10:53 am

I've decided to replace plugs as they burn out. In any case, glow plugs need to be removed when the engine is fully warmed up. You can start the engine with the intake manifold off. Just make sure that nothing get sucked into the 12 intake ports. Use a deep socket and long extension to help make sure that all of the force applied to the glow plug is rotational (not pulling it to one side).

I have done the Diesel Purge thing by filling the fine fuel filter and then clamping off the main tank return line. Not 100% Diesel Purge, and not the whole can, but close enough.
...Alan

Court
Posts: 812

Re: Air in Fuel Lines.

Post#160 » Thu Mar 26, 2020 11:34 am

Thanks Alan,

What do you use to clamp off the line and where do you do the clamping? I must say the lines are not easily accessible at least at first and second and third glance. I have been thinking ,,, would it be sensible to install a way to turn it off with some sort of valve rather than having to compress the rubber hose.... thinking that is not what a hose likes ,,,especially if you are an old hose.

Ok well ,,,, if I find it straightforward to remove the IM and replace and after testing the GPs they are ok I might leave them in place,,,, but sort of fearful that will eventually lead to them being seized in there. I do have maintenance records of sorts from Japan ,,,,but ,,, hard to decipher,,,, I will give that a more serious try.

Finally found some good videos of GP removal that also gives me comfort on the IM removal ,,, just need to get organized now. My return line hose still not delivered today. It will be in a UPS vehicle appropriately powered by diesel I hope!!

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